The International Astronomical Union (IAU) redefines the term "planet" such that Pluto is now considered a dwarf planet.

A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System. The prototypical dwarf planet is Pluto, which for decades was regarded as a planet before the "dwarf" concept was adopted in 2006.

Many planetary geologists consider dwarf planets and planetary-mass moons to be planets, but since 2006 the IAU and many astronomers have excluded them from the roster of planets.

Ceres - RC3 - Haulani Crater (22381131691)
Ceres - RC3 - Haulani Crater (22381131691) (Source: Wikimedia Commons)
Pluto in True Color - High-Res
Pluto in True Color - High-Res (Source: Wikimedia Commons)
Quaoar and moon Weywot JWST NIRCam
Quaoar and moon Weywot JWST NIRCam (Source: Wikimedia Commons)
Sedna PRC2004-14d
Sedna PRC2004-14d (Source: Wikimedia Commons)

Watch: Why Pluto Stopped Being a Planet | The Controversial 2006 Vote

From the Beyond Truth channel.

Sources and further reading: Wikipedia — Dwarf planet, International Astronomical Union, IAU definition of planet, Pluto (CC BY-SA). Images: Wikimedia Commons.